Preheat your oven to 180°C (160°C for fan assisted ovens) / Gas Mark 4.
Mix the eggs, oil, water and cake mix gently together and whisk (by hand or electric mixer) for 2-3 minutes until smooth and creamy. Remove 8 tablespoons and place in a smaller bowl and set aside.
Pour the mixture evenly into your greased cake tins. Empty the chocolate sachet into the mixture you set aside and stir well. Then spoon this into the mixture in the tins and using a rounded knife, gently swirl through.
Bake in the centre of the oven for 23-28 minutes or until a rounded knife inserted into the centre of the cake comes out clean, then cool on your cooling rack.
Ice the cakes together by using 2 large tablespoons of Chocolate Buttercream Style Icing. Use the remaining icing to cover the top and sides of the cake. Arrange the chocolate fingers around the sides of the cake, alternating a white finger with a dark finger until the cake is encased.
Decorate the top of the cake with chocolates, edible glitter and finish off your masterpiece with ribbon for a truly glamorous cake...Wonderful!